Most people come to San Agustín for the carved stone figures and leave without noticing that the Magdalena, Colombia's great river, starts just up the road and squeezes through a gorge two metres wide at the Estrecho.
This is the outfit that runs it. Rafting on the upper Magdalena, out on the Vía la Estrella at the edge of town.
Their booking link has the international dialling prefix 00 stuck on the front of the number, so the WhatsApp button on the site is broken as published. The number itself is right.